Перевод координат из радиан на JavaScript

gistfile1.js

// convert radians into latitude
    // 90 to -90
    function rad2lat(rad) {
        // first of all get everthing into the range -2pi to 2pi
        rad = rad % (Math.PI*2);

        // convert negatives to equivalent positive angle
        if (rad < 0)
            rad = 2*Math.PI + rad;
        
        // restict to 0 - 180
        var rad180 = rad % (Math.PI);
        
        // anything above 90 is subtracted from 180
        if (rad180 > Math.PI/2)
            rad180 = Math.PI - rad180;
        // if it is greater than 180 then make negative
        if (rad > Math.PI)
            rad = -rad180;
        else
            rad = rad180;

        return(rad/Math.PI*180);
    }

    // convert radians into longitude
    // 180 to -180
    function rad2lng(rad) {
        // first of all get everthing into the range -2pi to 2pi
        rad = rad % (Math.PI*2);
        if (rad < 0)
            rad = 2*Math.PI + rad;

        // convert negatives to equivalent positive angle
        var rad360 = rad % (Math.PI*2);         

        // anything above 90 is subtracted from 360
        if (rad360 > Math.PI)
            rad360 = Math.PI*2 - rad360;

        // if it is greater than 180 then make negative
        if (rad > Math.PI)
            rad = -rad360;
        else
            rad = rad360;

        return(rad/Math.PI*180);
    }